The use of contact lenses incorporating on or more curvatures for the correction of an individual's visual acuity is well known. A portion of the conventionally available contact lenses are manufactured using soft lens materials. When the soft contact lens is placed on-eye, the curvature of the lens is altered because the soft lens will, to a certain extent, drape onto the cornea. This is known as lens wrapping or flexure. Flexure can affect different parameters of the lens, such as diameter, sagittal depth, and the front and back surface curvatures, to varying extents. For example, the sagittal depth may be reduced by 20 percent and the radius of curvature may vary by 5 percent. The extent to which the lens curvature is altered due to wrapping depends on the lens design, the mechanical characteristics of the lens material, and the on-eye environment, such as geometry, pH, temperature and the like.
Some known lens design methods attempt to take into account lens flexure. For example, it is known to design the back surface of the lens so that it is a substantially duplicate of, and fits, the wearer's corneal topography. However, this is disadvantageous because the corneal surface varies from person to person and this method requires customizing the lens' back surface design to the individual. Additionally, this method requires the design and manufacture of complex back surfaces for each lens. Finally, these lenses must maintain perfect translational and rotational alignment on the eye to be effective.
Another known lens design method is to provide a lens design, test the design on-eye, change the design based on the testing, and repeat each of these steps until the design is optimized. This method is costly and cumbersome.